This question involves a slight misunderstanding of the roles in the post-trial process. A military judge’s role largely concludes after the sentence is announced and the trial is adjourned. The post-trial clemency process is between the defense counsel, the convening authority, and the convening authority’s legal advisor (the SJA). There is no formal “clemency advice” from the convening authority that a judge would override.
After the trial, the defense counsel submits a clemency petition to the convening authority, arguing for a reduction in the sentence. The SJA then provides their own, separate written recommendation to the convening authority. The convening authority, after considering both inputs, makes their final decision on the sentence. The military judge does not participate in or override this command-level clemency decision.
If the defense objects to the content of the SJA’s recommendation to the convening authority (for example, if it contains factual errors or is legally incorrect), their recourse is not to go back to the trial judge. Instead, they will submit a rebuttal to the SJA’s recommendation. If the convening authority still makes an adverse decision, the defense’s objection to the flawed legal advice then becomes a primary issue for the appeal filed with the service’s Court of Criminal Appeals. It is the appellate judges, not the trial judge, who would review and potentially provide a remedy for any errors in the post-trial advice process.